Energy Impact of Ventilation and Dynamic Insulation.

Dynamic insulation stands for an insulation through which an air flow flows. The air flow is usually the normal ventilation flow. The air can flow in the same or in the opposite direction of the normal heat flow. The dynamic insulation can be arranged as single where only inlet or exhaust air passes the insulation, or as combined where inlet and exhaust air pass one half of the insulation each. Dynamic insulation using exhaust air might result in condensation problems in cold climates. The normal insulation heat loss is reduced when using dynamic insulation and can be eliminated more or less only if the ventilation heat loss is several times larger than the normal insulation heat loss. The reduction of normal insulation and ventilation heat losses when using dynamic insulation is limited to 0.23 for single and 0.35 for combined dynamic insulation. Dynamic insulation can be regarded as a ventilation heat recovery system. The equivalent ventilation heat recovery efficiency is limited to 0.5 for single dynamic insulation and to 1 for combined dynamic insulation, and decreases with increasing ventilation flow. An alternative to dynamic insulation in order to obtain the same saving is standard ventilation heat recovery system.